Upon inoculation of A549 cells, the G and SH mutant viruses induced similarly low levels of IFN, compared to the HMPVWT and negative-control parainfluenza virus type 5 (PIV-5) (Fig. 3a), while infection efficiencies of SH and G mutant viruses were above 60% (Fig. 3b). The gene discussed is IFNA1; the disease is infection.